According to the well-connected John Gruber, iOS users will see a difference in the operating system's UI when iOS 7 is released presumably alongside the next-generation iPhone, but Apple is struggling to implement the changes on time.

Gruber, who runs Apple blog Daring Fireball, said Senior Vice President of Industrial Design and new head of Human Interface Jony Ive has apparently made noticeable visual tweaks to Apple's mobile platform. So much so, that "word on the street" has it that iOS engineers are required to put a polarizing filter over their iPhone displays to prevent onlookers from getting a glimpse of the new UI.

The rumor was revealed in a Branch discussion regarding the latest Apple talk, with a number of well-known bloggers airing out their thoughts on what the company has in store for 2013.

Rene Ritchie of iMore, another well-informed blogger, chimed in, saying, "Ive's work is apparently making many people really happy, but will also apparently make rich-texture-loving designers sad." The quip is in regard to the skeuomorphic designs seen in iOS 6, such as the stitching elements found in Apple's Find My Friends app.

Gruber claims that iOS 7 development is "running behind," prompting OS X 10.9 engineers to be pulled from their work to lend a hand in getting the mobile OS ready in time for launch.